# include <cstdio>
#include <ctime>
#define CLK_TCK 100
#include <iostream>
#include <iomanip>
using namespace std;


int main () {
	int c1,c2;
	cin>>c1>>c2;
	int sum_sec = (1.0*(c2-c1)/CLK_TCK)+0.5;
//	cout<<"c2-c1 = "<<c2-c1<<endl;
//	cout<<"sum_sec = "<<sum_sec<<endl;


//	int sec,min,hour;
//	hour = sum_sec/(3600);
//	min = (sum_sec-hour*(3600))/(60);
//	sec = (sum_sec-hour*(60*60)-min*(60));
//
//	cout<<setw(2)<<setfill('0')<<hour<<":"<<setw(2)<<setfill('0')<<min<<":"<<setw(2)<<setfill('0')<<sec;
	printf("%02d:%02d:%02d",sum_sec/3600,(sum_sec%3600)/60,sum_sec%60);

	return 0;
}
